Perth dad 'killed family in home, stayed'

A Perth father allegedly used a blunt instrument and knives to murder his three young daughters, their mother and grandmother and then stayed in the house with their bodies for days before heading north to turn himself in.

The bodies of Mara Lee Harvey, 41, her three-year-old daughter Charlotte, two-year-old twins Alice and Beatrix and their grandmother Beverley Ann Quinn, 73, were found inside the Bedford home on Sunday.

It is alleged Anthony Robert Harvey, 24, killed his wife and children on September 3, then killed his mother-in-law the next morning when she came to visit.

It is the third domestic mass killing in Western Australia in four months.

A grandfather shot his wife, daughter and her four children before taking his own life at a farm in Osmington, near Margaret River, in May.

Just over two months later, a 19-year-old man allegedly murdered his mother, sister and brother in Ellenbrook in Perth's northeast.

The latest grisly discovery came after Harvey turned himself in at Pannawonica police station, some 1500 kilometres north of Perth.